AppearanceAppearance Emerald green crystallineChemical Specifications Appearance Colourless crystals or white crystalline powder Assay (as Mg (NO3)2.6H2O) Min 98.0% pH (5% solution in water; 25°C) 4.0 - 8.5 Chloride (Cl) Max 0.005% Sulphate (SO4) Max 0.01% Heavy metal (as Pb) Max 0.001% Iron (Fe) Max 0.001% powder Assay Min 98% Chloride (Cl) Max 0.01% Alkalis (as Na) Max 0.1% Cobalt (Co) Max 0.5% Iron (Fe) Max 0.02% Heavy metal (as Pb) Max 0.04% Red to brownish color solution Sensitivity as an indicator Passes test